Brake control device



Sept 2, 1941- M. s. GRAVES BRAKE CONTROL DEVICE Filed Oct. 1'7, 1938Mdr/ Si Graves Patented Sept. 2, 1941 UNITED STATES PATENT oFFlcE2,254,523 BRAKE coN'rnoL nEvIcE Mark S. Graves, Los Angeles, Calif.

, Application October 17, 1938, Serial No. 235,373

2 Claims.

This invention relates to a device for controlling iluid pressureoperated brakes such as are employed on motor vehicles, and moreparticularly pertains to a device for automatically preventing releaseof the brakes while the vehicle clutch pedal is held in a clutchdisengaging position; the present invention being an improvement on theconstruction set forth in my application for Letters Patent SerialNumber 172,562 filed November 3, 1937, now Patent No. 2,152,686, grantedApril 4, 1939.

lAn object of the invention is to provide a device of the abovecharacter embodying a. selfclosing control valve arranged in the fluidpressure delivery line of a uid pressure operated brake system in whichthe valve is so arranged as to open under the flow of fluid underpressure from the source `of pressure supply to the brake mechanism andto automatically close on cessation of the flow of fluid pressure so asto prevent the release of the brakes in event the vehicle clutch isdisengaged; the invention embodying a mechanism associated with theclutch operating mechanism for holding the control valve in its openposition while the clutch kmechanism is engaged and to release thecontrol valve on placing the vehicle clutch in its released position ondepression of the clutch operating foot pedal.

Another object of the invention is to provide a control valve of thecharacter above described so mounted and arranged as to be gravityoperated to its closed position and which will so operate irrespectiveof any direction of inclina- K Another object is to provide anarrangement whereby the control valve may be operated and utilized as anemergency brake independent of the clutch control mechanism.

Another object is to provide a construction in the control valve forrelieving excessive pressures as may be developed in the brake line byrepeated operation of the brake pedal, so as to permit such repeatedoperations of the pedal without danger of bursting the brake lines orthe brake actuating parts, and in which the de- 55 vice may be set toeiiect by-passing of the brake operating iluid at any predeterminedpressure.v

A further object is to provide a device of the above character which isadapted to be aDPlied'T-f" to a motor vehicle Without connecting toaypart of the clutch mechanism and whereby it may be easily installed asan accessory in most automobiles of conventional construction now inuse.

With the foregoing objects in view, together with such other objects andadvantages as may subsequently appear, the invention is carried intoeffect as illustrated by way of example in the accompanying drawing inwhich:

Fig. 1 is a diagram in side elevation depicting the invention asapplied;

Fig. 2 is a section and plan view taken on the line 2--2 of Fig. 1;

Fig. 3 is a view in vertical section taken on the line 3-3 of Fig. lshowing the construction and mode-of operation of the control valve;

Fig. 4 is a detail in section and elevation taken on the line I-l ofFig. 3 showing the manner in which the control valve is held in its openposition;

Fig. 5 is a detail in section depicting a modied form f the valveoperating structure.

Referring to the drawing more specically A indicates generally themaster cylinder oi a hydraulic brake system which is or the usual typeand embodies a, cylinder and piston (not shown) for creating a fluidpressure in the system in effecting application of the brakes; thepiston being attached to a connectingrod 6 operatively connected to abrake pedal 1.

Leading from the master cylinder A is a fluid conductor 8 which leads tothe'wheel brakes B (only one being diagrammatically illustrated) inwhich conductor is arranged a control valve indicated generally at C.

The control valve C. embodies an upstandlng cylindrical valve housing 9formed intermediate its ends with a, valve seat lll and fitted with anupwardly opening valve D which is adapted to normally gravitate to aclosed position on the seat Ill. The housing 9 is fitted at its lowerend with a cap Il formed with a nipple I2 opening to the interior of thelower end portion of the housing and which nipple is attached by acoupling I3 to the length of the conduit 8 leading from the fluidpressure supply in the master cylinder A. The upper end of the housing 9is tted with a cap I4 on which is formed a nipple I opening to theinterior of the upper end portion of the housing 8 and to which nippleis atthrough'which the shaft l1 extends.

2' tached by a coupling II the portion of the conduit leding t thtbrakes B.

Means are provided for holding the valve D in an open position whichmeans embodies a rockvshaft I1 extending laterally into. the housing lthrough a packing gland I8 carried on the latter, and on which shaft ismounted interiorly of the housing an upstanding finger l5 which.

when disposed in an upright position lwill serve to prevent the valve D`fromadvancing to its closed position on the valve seat` Il,-but whichfinger I9 is adapted on turning the rock shaft I1 to be positioned outof engagement with the' gagement therewith.

' The inner end of the shaft I1 seats in a socket 2l in the side wall ofthe housing 9 opposite that for' holding the shaft l1 against excessivelongitudinal movement, as under the influence of vibrations, the shaftis formed intermediateits ends with screw threads 2| which have threadedAGi sumciently to effect the requisite rocking 0f the lever arm 25 'andshaft I1 as will presently be described.

In the construction shown ln Fig. 1 the stem 21 extends at an acuteangle relative to the link 2t and the -outer end of the link 25, ispivotally connected directly to the lower end of the stem wherebydownward movement of the stem 21 vwill exert a direct longitudinal pullon the link 25 to advance the arm 25. A spring 22 connects -with-the arm25 and with a fixed member I4 and position and to act through the link25 to dis- Dose the stem 21 in its normal uppermost position --andinwhlch position of the arm 25 the nnger As a means nected to the linkand the other arm of which connection 31.

engagement with the valvehousing 9; the threads 2I permitting therequisite slight rotary movement of the shaft in effecting operation ofthe valve with but slight longitudinal movement of the shaft. Thisthreaded connection between the shaft and the valve housing alsoservesin cooperation with the packing gland I 5 to prevent leakage of thebrake operating fluid from the interior of the valve housing to theexterior thereof along the shaft I1. K-

The finger I9 is mounted on a hub 22-formed with an opening 22 adaptedto receive the inner end of -the shaft I1 and which hub is fitted with aset screw 24 for leilectingengagement withv the shaft I1 to hold the hub22 and finger I5 against turning on the shaft. In assembling the hub onthe shaft it is positioned interiorly of the valve housing 9 through theopen end 'of the latter afforded on Vremoval of the cap the hub. beinginitially positioned within the valve housing with the finger I9thereon-presented t0- ward the valve D and being held therein until theshaft I1 is screwedinto place with the inner end thereof passing throughthe hub 22 and extending into the-recess-2II and whereupon the set screw24 is tightened into engagement with theshaft |1. 1 y y The outer end ofthe shaft uI1 is'ilttedwith a crank arm 25 to which is pivotallyattached a link 26 leading to a reciprocal operating'stem 21 so arrangedand connected to the link .25 that longitudinal movement of the stemwill act through the link 26 to turn the shaft I1 a partial revolution.The stem 21 `is here shownas slidably supported in a guide way 28carriedon the steering wheel column 29 of the motorvehicle. The upperouter end of the stem 21 is formed with a. bend 3|! which leads to apoint adjacent to but spaced from the tread 3| of a clutch operl! ontheshaft |1 will be disposed in its upright position to hold the valve Doff its seat and in an open position. v

In the arrangement shownin Fig. 5 ,the outer end of the link 25 isindirectly connected to the stem 2 1 through a bell crank lever 35pivoted at 35, one arm of which lever is pivotally conis connected tothe stem 21v by a pin and slot A spring Il is interposed between theguide way 22 and the bend Il on the steml 21 -to normally maintain thelatter in` its uppermost position and which springmay operate inconjunction with the spring 3l' or in lieu thereof in holding the valveD in its open Position.

ber 42 below the valve seat Il; the passage 4l. being here shownasformed with an upwardlyV extending portion" a communicating with thechamber -4I and having a seat b on which the ball valve E normally restsunder the urge of a spring c which bears between the valve E and anadjustable screw plug` d threaded in an extension e of the .passage a;the -passage extension e opening upwardly at the upper end of thepassage a which communicateswith the chamating foot pedal 32; theextension 30 being so` located that when the footpedal 32 is depressedby the foot of the operator the extension 30' will be in the path of thedownward movement of a portion of the operators shoe projecting A'io 'varied to meet ber 42.-` The adjustable plug d'aifords a means forvarying the tension ofthe spring c to vary the resistance to `opening ofthe valve- E. and

whereby the point of pressure relief may be varying conditions asoccasion may require.

Normally the parts -are disposed as shown in full lines in the drawings,that is, with the valve D held in its open positionY by the upstandingfinger 9 under the urge of the spring 22 or ll in exerting a pull onjthe arm 25,` that is, while the Vclutch lever 32 is in thenormallyretracted position it occupies when the clutch controlledthereby is in its engaged position. While the valve D is thus maintainedopen flow of the brake operatingiluid mayoccur in either direcv tionthrough the valve housing 9, butwhen the valve D is' in its closedposition such now is restricted to the direction leading from the mastercylinder A to the brakes B. It follows 'that in the operation of theinvention, when the clutch lever 25 is disposed in its normal retractedposition with the clutch in its engaged position, and the valve D heldin its open position, the vehicle brakes B may be freely applied andreleased by operation of the brake lever 1 in the usual manner; but ondepressing the clutch lever to release the clutch then the rock shaft I1will be turned by the forward movement of the operators foot on thetread of the clutch lever through the link 26, so as to move the fingerI9 from beneath the valve D thereby allowing the latter to advance toits closed position. When this occurs and the brakes are applied whilethe clutch lever is advanced Yand the clutch is disengaged, release ofthe brakes will be prevented by reason of the valve D then being closedso as to conne the brake operating fluid in the conduit B between thevalve and the brakes B.

until such time as the clutch lever is released to re-engage the clutch.

In event it is desired to effect closing of the valve D independent ofoperation of the clutch. such may be accomplished by the operator merelyby shifting his foot from the tread Il into engagement with the endportion 30 of the stem 21 and then depressing the latter. The action isdesirable where the vehicle is stopped on a grade with the motor runningand the clutch engaged with the transmission in neutral; closing of thevalve D and at the same time applying the brakes by operation of thebrake lever sewing to permit release of the brake lever while the stem21 is depressed and the valve D thus maintained closed. withouteifeoting release of the brakes. In thus employing the invention, theclutch is iirst disengaged by depressing the clutch lever 32 independentof the valve control stem In event of repeated operations of the brakelever while the valve D is closed, the successive applications willdevelop increasing pressures in V the brake line forward of the valve Dand such as might burst the line or blow out the brake cylinder, but bythe provision of the relief valve E such action will be prevented, sinceon a pressure being developed forward of the valve D as will overcomethe spring c the latter will yield and permit opening of the valve E sothat a portion of the brake operating fluid forward of the valve D maybe passed back to the other side of the valve D through the passage l0,on release of the brake lever.

While I have shown and described a, specific embodiment of my inventionI do not limit myself to the exact details of construction set forth,and the invention embraces such changes, modiiications and equivalentsof theV parts and their formation and arrangement as come within thepurview of the appended claims.

I claim:

1. A valve for brake control systems embodying a housing having apassage leading therethrough, a valve seat intermediate the ends of saidpassage. a ball valve in said passage' above said seat, a rock shaftextending through said f housing into said passage below said seat, aiin- 21 so as to permit disposing the vehicle transmission in neutral inthe well known manner. To release the brakes after such operatic thebrake lever is rst depressed to hold Athe brake operating uid underpressure, whereupon the stem IlisreleasedandpermittedtoreturntonormalwhereuponthevalveDwillbeopened so astopermitbackflowofthebrakeoperating fluid on retraction of the brake lever. The clutch leveristhenoperatedtopermitplacingthe transmission in gear in the usualmanner.

ger on said shaft engageable with said valve to lift it from said seat,and a screw threaded connection between said shaft andhvalve housing onwhich said shaft is turnable, and spring means for exerting a turningforce on and holding said shaft with the Vfinger thereon holding thevalve in its' open position.

2. A valve for brake control systems embodying ing a housing having apassage leading therethrough, a valve seat in said passage, a valve insaid passage, a rock shaft' in said housing, a

finger on said shaft engageable with said valve t0 .lift it from saidseat. a screw threaded connection between said shaft and valve housingon which said shaft is turnable, spring means tending to turn andthereby normally holding said shaft with the finger thereon holding thevalve in its open position. n

y l MARK S. GRAVE.

